The invention relates to a fastening device for an adjustable front plate of an extractable furniture part, in particular for a drawer, the device including a supporting part fastened to each side of the furniture part, in particular to the guide rails of a pull-out guide assembly, and a holding part fastened to each side of the front plate. The holding parts and supporting parts at upper and lower bearing points thereof are attached to each other by means of screws or the like. The upper screws are held by flaps pivotably mounted on the supporting parts about axes extending parallel to the front plate.